In the course of modern microcomputer technology, it has also become known to use microcomputers for hearing aids for hearing-impaired persons. To this end, the analog input signal of the microphone must be converted into a data word and then the output data word, which was formed by digital conversion in the microcomputer in accordance with the desired auditory function, must in turn be delivered as an analog signal to an electro-acoustic converter (for example a receiver). It has now been found that the opportunities afforded by a microcomputer for this purpose are often insufficiently well exploited and a desire for greater versatility exists.